Carton blank



FIG. 1 is an isometric view of a carton blank, showing my design;

FIG. 2 is a top view of thereof;

FIG. 3 is a bottom view thereof;

FIG. 4 is a front view thereof;

FIG. 5 is a rear view thereof;

FIG. 6 is a left side view thereof; and,

FIG. 7 is a right side view thereof.

The broken lines in the drawings depict fold lines and form a part of the claimed design. 

CLAIM The ornamental design for a carton blank, as shown and described. 